Improvement in lathe-chucks



l UNITED STATES PATENT @EEicE JAMES A. BUNCE, OF EAST BERLIN, CONNECTICUT.

llVlPiROVEMENT IN LATHE-CHUCKS.

To all whom 'it may concern:

BeitJ known that I, JAMES A. BUNOE, of East Berlin, county of Hartford, and State of Connecticut, have invented certain new and useful Improvements in Self-Centerin g Chucks; and I do hereby declare that the same is described and represen ted in the following' specication and drawings; and to enable others skilled in the art to make and use the same I will nroceed to describe by referring to the drawings, in which the saine letters indicate like parts in each of the figures.

The nature of this improvement will be understood from the specification and drawings.

The 'object desired to be attained thereby is to prflucea chuck which shall possess all the requisite qualities of those now in use, and at the same time be simpler and cheaper of manufact-ure.

In the accompanying' drawings, Figure l is aseefon-al View through the center of the chuck, as shown by the line a. Fig. 2 is au end view, showing the sliding dovctail wedge-sh aped bar, which unites with a corresponding-sh aped join t andjaw for moving in and out the jaws.

A s the stock, made of any suitable material and having slits cut or formed in the outer end, in which to allow thejaws B to work closely and i'reely back and forth in a rightangle line with the stock, and having a rabbet-recess, c, on each side of the face en d of said stock to re- ,eeive the iiange eglgerl, formed on each side of the endgofthejaws. It (the stock) is also provid. with grooves or recess e, in which to allow the sliding dovetail wed ge-sha-ped bar C to work closely and freely to operate the jaws in` and out, as desirable. The outer surface ot' this stock has a screw-thread cut thereon.

D is a sheath having a screw-thread cut on theiuside, so as to iit closely and' work freely on the stock A. The inside of this sheath, and back a proper distance from the front end thereof, is turned out smoothly to the bottom of the thread, and has a groove or recess, z', formed therein to receive the lip or flange 7i', formed on the back end of the sliding bar C. After the stock A is prepared the sheath is screwed thereon until the groove 'i in the sheath D is nearly down to the lower end of the opening to receive and hold thejaws B, when the lip 7c of the sliding han@ is inserted into said groove t', and the sheath turned onto the stock, drawing therewith the bars C into the grooves or recess e, until the outer ends, (wedge and dovetail ends,) a 0, are about even with the face end ofthe stock.

When thejaws B are respectively inserted to their places upon the dovetails n, then the cap F, which is made so as to just lit onto said stock over the threads and the outer edges of the sliding bars, C, against which the outer edges of the said sliding bars work back and forth as the sheath D is turned to move the jaws B in or out in said cap. The face ofthe jaws work back and forth against the` inside face of the cap.

Thus all the parts are or may be made in duplicate form, so that any one piece will lit any other part or chuck. and are put together in working order and held in place by screws passing through the face ot' the cap into the end ot' the stock. This chuck is designed to be secured upon a spindle in the usual way.

I believeI have thus shown the nature, con struction, and operation of this improvement,

so as to enable others skilled to make and use the same.

That I claim, therefore,` and desire to secure by Letters Patent, is- The combination of the sliding bars C with the jaws B, sheath D, and stock, A, substantiallyin the manner as and forthe purpose described.

JAMES A. BUNCE. 

